Well, maybe. It depends on the neighborhood. Meal Mart tried to open that chassidish-style restaurant in the Wesley Hills area and it bombed, because it was the wrong neighborhood for it. There are very few chassidim in the area to go. But there are many successful businesses in that shopping center which do fine without chassidish clientele.
It’s for sure easier to do well if you have things like chassidishe hashgachos, particularly in the 306/59 area. (Yogenfruz motzaei Shabbos is basically all chassidish couples.) But I’d dispute that in Monsey the only way to keep a place open and successful is to appeal to chassidim. I see all the time how really huge even the non-chassidish population of Monsey is, mostly because I live in a very non-chassidish area.